Method of producing castings utilizing overlapping gates



Jan. 14, 1958 H. MORIN 2,819,494

METHOD OF PRODUCING CASTINGS UTILIZING OVERLAPPING GATES Filed may 10, 1955 INVENTOR. mounsj H. MORIN Afi orney f United States Patent METHOD OF PRODUCING CASTINGS UTILIZING OVERLAPPING GATES Louis H. Morin, Bronx, N. Y. Application May 10, 1955, Serial No. 507,326 9 Claims. (Cl. 18-55) This invention relates to the production of castings employing separate parts cast one upon the other in forming an assemblage of relatively movable parts. More particularly, the invention deals with a simple method of utilizing overlapped gates, whereby the assembled parts may be cast one upon the other by utilizing relatively short gates, thereby insuring the formation of perfect castings and, further, minimizing the amount of material formed in the gates, thus reducing the amount of material injected into the die cavities in each injection shot of the machine.

The novel features of the invention will be best understood from the following description, when taken together with the accompanying drawing, in which certain embodiments of the invention are disclosed and, in which, the separate parts are designated by suitable reference characters in each of the views and, in which:

Fig. 1 is a diagrammatic view, illustrating the formation of two cast parts in assembled relationship upon a movable core, one part of the die being diagrammatically indicated in dotdash lines.

Fig. 2 is an enlarged section on the line 2-2 of Fig. 1, also diagrammatically indicating in dot-dash lines the die halves and further indicating in dotted lines an added step in the formation of one of the cast par-ts upon removal from the die.

Fig. 3 is a detailed view of a product made according to the method disclosed in Figs. 1 and 2, with part of the structure broken away and in section and with one part in a different position from that shown in Figs. 1 and 2; and

' lower position, as noted at 23' in Fig. 1.

Fig. 4 is a face view of another form of die which I employ, diagrammatically showing the formation of other two-part relatively movable castings.

This application constitutes a continuation-in-part of my prior applications, Serial Number 283,916, filed April 23, 1952, now Patent No. 2,777,166, and Serial Number 285,449, filed May 1, 1952, now Patent No. 2,768,415, respectively.

In Figs. 1 and 2 of the drawing, I have diagrammatically shown one method of producing a product employing two die cast parts, which are cast one upon the other, in which overlapping gates are employed. The product in question is illustrated more in detail in Fig. 3 of the drawing and is in the form of a buckle, comprising a main, generally O-shaped body part 10, defined by a large somewhat flattened end wall 11, a round end wall 12 and round side walls 13 and 14, which converge into the end wall 11, as seen at 15. The side walls 13 and 14 have, on their inner surfaces, opposed pivot knobs or members 16 and 17, respectively, forming pivot bearings for the second part 18 of the buckle. The part 18 comprises a rod-like member 19, having recessed ends, one of which is shown in section at 20, to receive the pivot knobs or members 16 and 17 for free limited rotary movement of the part 18 thereon in moving the prongs 21 of the part 18 toward and from the end wall 11 in the use of the buckle. One surface of the end wall 11, preferably,

2,819,494 H Patented .lan. 14, 1958 2 includes recesses 22 to receive the prongs 21. The prongs 21 are tapered and, in the final formation of the prongs, in other words, after they have been moulded straight, as indicated in Fig. 2 of the drawing, the contracted ends are, preferably, bent or offset to a slight extent, as indicated in dotted lines at 21 in Fig. 2 of the drawing.

Now turning to Figs. 1 and 2, here is diagrammatically illustrated the method of producing the buckle 10. In Fig. 1 is diagrammatically shown the result of a complete casting operation by injection of heated material through the gate 23 to form, around a transfer core pin 24, an open ring-like gate portion 25, from which extends another gate 26. The gate 26 opens into a cavity of a die, diagrammatically indicated at 27, to form the body 10, including the knobs or pivot members 16 and 17, as well as the other parts heretofore specifically described.

The gate 26 is disposed solely in one half of the die. However, this gate communicates with a gate 28, located solely in the other die half at a position below the gate 26, as clearly noted in Fig. 1 of the drawing. These two gates are joined by a bridging gate 29, noted in Fig. 1 of the drawing, so that, in the pressure injection of casting material into the gate 23 to form the cast part 10, material is also transmitted through the gate 29 to the gate 28 to simultaneously form the cast part 18 on a pre-cast part 10', which is then positioned in the lower part of the die by movement into such position by the transfer core pin 24.

In this transfer, it will be apparent that the open ring 25 shifts to the lower position which is indicated at 25 in Fig. 1, and the preformed gate 23 also assumes this "ice It will be apparent that, in the initial or first shot of the machine, a non-useable part. will be formed in the lower cavity. Thereafter, in the movement of the part 10 into the lowered position, as noted at 10', in the second shot, a finished product constituting an assemblage of 10 and 18 will be formed. Then, in moving the next or third part 10 downwardly, the assemblage of 10' and 18 is moved beyond the limit of the die and trimmed to remove the gate therefrom, thus producing the finished product, as noted in Fig. 3 of the drawing. As pre- VlOllSlY stated, the prongs 21 of the part 18 are initially formed in the manner illustrated in Fig. 2 of the drawing, and are later shaped by bending, as noted at 21'.

It will also appear, from a consideration of Fig. 2 of the drawing, that the gate 28 extends itself around the end 12 of the part 10, as seen at 28', in directing the material to the part 18. No adhesion takes place between the gate portion 28' and the end 12 of the part 10. In the trimming operation, the gate 28, 28 is removed from the part 18, at 30; whereas, the gate 26 is removed from the end 12 of the part 10, at 30'. It will be apparent, from a consideration of Fig. 1, that, after 10 has been fed beyond the limit of the lower part of the die, in moving 10 into the lowered position, the dies are partially closed and the core pin 24 is raised back to the position indicated in Fig. 1, in which operation, the core pin is stripped from the open ring 25 of the gate, then attached to 10'. The trimming operation in question takes place beyond the limits of the die.

In Fig. 4 of the drawing, I have shown another adaptation of the method and, in said figure, 31 represents the face of one part of a die, having cavities 32 and 33 in vertical alinement. At 34 is shown the primary gate, into which heated material is pressure injected simultaneously into the cavities 32' and 33 through the gate passages 35 and 36.

At 37 isshown a core and transfer pin. This pin, from the point 38 to its lower end 39, has a slight taper to form, in the moulded product part 40, a longitudinal slightly tapered bore 41, the tapers not being shown.

The'ptoduet paft is foimed in the cavity 32 and comprises an elongated tubular member having an enlarged central collar 42 with a rounded bearing surface 43. The die 31 has upper, lower and intermediate bores 44, 45 and 46, respectively, in -which the core and transfer-pi 37 operates. It will be noted that the lower end 39 of the pin 37 terminates normally midway of the bore 46.

Simul aneously in casting or moulding the product part 40, another product part 47 is formed in cavity 33, the heat d material being directed to the cavity 33 through the gate 36. At this time, it will be apparent that th gate 35 will be in one half only of the die; whereas, the gate 36 is in the other half of the die, so that the gate 36 crosses the gate 35in the position 35' at 48, similar to the crossing of the gates '26 and as, as noted in Fig. 2 of the drawing.

The product part 47 comprises a ring 49, moulded directly upon the collar 42 of a product part 40, when in the position 40', that is to say, disposed in the cavity 33, the cavity 33 being sha ed to include the product art 40 as well as the product part 41. The ring 419 has a rounded socket 50, which tits on the rounded surface 43 of the collar 42 to provide, in the resulting assemblage, rotary as well as swinging movement of the product part 47 on the product part 40.

The product part 47 includes also,- at one side thereof, a hexagon nut 51, joining the ring in a neck portion 52 and beyond the nut 51 is a reduced externally threaded extension 53. The latter provides means for mounting the product part 47 in connection with a suitable support. It will also appear that the die includes a bore 54 for receiving the gate 36 in the lowered position, is indicated at3 The procedure of forming the assembled east or moulded product parts 40, 47 will be similar to the pro cedure of forming the assembled partslo and '18 in Figs. -1 to 3, inclusive. In other words, after one injection charge of the heated material, the dies are opened and the core and transfer pin 37 moves downwardly to position the moulded product part 40 in the position 40'; whereupon, in closing the dies and forming the next injection shot, another part 40 is formed and the product part 47 is formed upon pte-cast part 40, then in the position 40'. It will also be apparent that, in again feeding the pin 37 downwardly, the product part 47 arranged upon the part 40' is fed beyond the lower limits of the die, the die partially closed and the pin 37 stripped from the assemblage 47, 40' in returning the pin 37 to the position shown in Fig. 4,- preparatory for the next injection shot of heated material.

Beyond the limits of the die, the product parts 40, 47 are trimmed at 55 and 56, respectively, to remove the gates 34, 35, 36, thus producing the finished assembled two-part product, the parts being relatively movable one with respect to the other.

With my improved method, two cast or moulded plastics are united and, in the resulting assemblage, the parts move relatively to each other, thus materially simplifying and economizing on the production cost of the resulting product. Further, this is accomplished without the use of extensive gating by reason of my method of overlapping the gates, in the manner clearly set forth. it will be understood, as set forth in said copending application Ser. No. 285,449, filed May 1, 1 952, now Patent No. 2,768,415, that the two parts of buckle or of ball joint 47 become relatively movable simply by subjecting them to a slight stress or holding one part and moving the other to break the slight seizure that has developed between the two parts Not only are long gates avoided by the present method in instances where they might possibly be employed, but in some instances, as illustrated by the buckle 10 and the ball type joint 47, products may be made which could not otherwise be formed by casting a second part in engagement with a previously cast first part; other strain, as by manually words, the buckle 10 or joint 47 could not be formed using 3 long "CiillltOlIS 281$ dis osed partly in CH8 and partly in the other die half.

As may be apparent, the method is suitable for forming a casting consisting of engaged parts. The parts may be relatively movable, as described, or relatively immovable. The engaged parts may be separable to provide one or more products, as described in said copending application Ser. 283,916, filed April 23, 1952, now Patent No. 2,777,166, where the final product consists of a single casting, although requiring for its production the formation of two other parts, latei' removed, in engagement with it; or, as described in cqpendingapplication Ser. No. 282,229, filed April 14, 1952, of which the present application is a continuation-in-part, two engaged parts may be formed and then separated to give two products.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:

l. The herein described method of producing two-part roducts which comprises simultaneously moulding each of the parts in a pair of relatively movable dies, the parts being spaces with re pect to each other in the dies, gating the first part primarily in one die, gating the second part. primarily in the other die with the gate of the second part crossing the gate of the first part, shifting both parts to move the second part out of the dies and the first part to another position between the dies, and forming a subsequent part like said second part in assembled relatio ship to the shifted first part.

2. The herein desetibed method of producing two-part product which comprises moulding a first part in a pair of relatively movable dies, gating the first part primarily in one die, shifti g the firstp'ar't with its attached gate to another position between said dies, forn'1ing a second part in assembled relation to the shifted first art, and gating the second part primarily in the other die with the gate or the second part crossin the gate of the first part.

3. Method of forming castings each consisting of engaged parts .by means of a pair of relatively movable mating dies having spaced cavities and gate channels which comprises positioning a movable transfer rod between said dies, injecting casting materials to a first cavity and about said rod through a first gate channel disposed solely in one die to form afirst part and a first attached 'g'ate; separating the dies and supporting said first part and gate by means of the rod, moving the rod to position the first part in a second cavity and simultaneously to position said attached gate in a second gate channel disposed solely in said one die, stripping the rod and returning the same to its ori inal position; injecting casting material to said second cavity through a third gate channel dis posed solely in the other die and intersecting the second gate channel to form a second part in engagement with said first p'ar't andsi'multaneously injecting casting material through the first gate channel to the first cavity to form an additional first part and additional attached gate; said second part being formed with a second attached gate which corresponds to the third gate channel, crosses said first gate which isdiseosed in the second gate chanfuel, and joins said additional gate in the first gate channe'l; separating the dies, moving the rod to move said engaged parts out of the second cavity and also to move said additional first part and additional attached ate from the first cavity to the second cavity, and continuing to form successive castings as above set forth.

4. Method of forming castings each consisting of enga ed parts by means 'of a pair of relatively movable mating dies having spaced cavities and gate channels which c mprises injecting casting material to a first cavity through a first gate channel disposed solely in one die to form a first part and a first attached gate; separating the dies, moving said first p rt and attached ate o position the first part in a see oiideavity and said attached gate in a second ate channel, said second game channel bein disposed solely in said one die; injecting casting material to said second cavity through a third gate channel disposed solely in the other die and intersecting the second gate channel to form a second part in engagement with said first part and simultaneously injecting casting material through the first gate channel to the first cavity to form an additional first part and additional attached gate; said second part being formed with a second attached gate which corresponds to the third gate channel, crosses said first gate which is disposed in the second gate channel, and joins said additional gate in the first gate channel; separating the dies, moving said engaged parts out of the second cavity and also moving said additional first part and additional attached gate from the first cavity to the second cavity.

5. Method of forming castings by means of a pair of relatively movable mating dies having a pair of spaced cavities and a gate channel which discharges casting material into each cavity, which comprises injecting casting material to one cavity through a first gate channel having a discharge portion disposed Wholly in one die and simultaneously therewith injecting casting material to the second cavity through a second gate channel having a discharge portion disposed wholly in the other die, thereby forming in said cavities a first and second cast part each having a gate attach-ed thereto, moving said parts and attached gates to move the second part and attached gate thereof out of the dies and to position the first part in the second cavity and the attached gate thereof in a third gate channel, again injecting casting material to said cavities to form additional first and second parts each having a gate attached thereto, and crossing said gate of the second additional part over the gate disposed in said third gate channel.

6. Method of forming castings by means of a pair of relatively movable mating dies which comprises injecting casting material to a die cavity through a gate channel having a discharge portion disposed wholly in one die, thereby forming a cast part having an attached gate, moving said part and attached gate to position the part in a second die cavity spaced from said first cavity and also to position said attached gate in a second gate channel having a discharge portion disposed wholly in said one die, injecting casting material to said second cavity through a third gate channel having a discharge portion disposed wholly in the other die to form a second cast part in engagement with said first part, said second part having an attached gate formed in said third gate channel, and, simultaneously with said last-mentioned injecting step, forming the gate of said second part so that it crosses the gate in said second channel.

7. Method of claim 6 in which said cast parts consist of relatively movable parts.

8. Method of claim 6 in which said cast parts consist of relatively immovable parts.

9. Method of claim 7 in which said cast parts are separable to provide at least one product part.

References Cited in the file of this patent UNITED STATES PATENTS 2,577,350 Morin Dec. 4, 1951 

